AD 90-26-09

90-26-09 BOEING: Amendment 39-6835. Docket No. 90-NM-42-AD.

Applicability: Model 727 series airplanes, listed in Boeing Service Bulletin 727-53- 0084, Revision 4, dated August 2, 1990, certificated in any category.

Compliance: Required as indicated, unless previously accomplished.

To prevent loss of cabin pressurization due to delamination, cracking, and/or corrosion of fuselage skin circumferential joints, accomplish the following:

A. Within the next 15 months after the effective date of this AD, accomplish an external visual inspection in accordance with Part II.A. of the Accomplishment Instructions of Boeing Service Bulletin 727-53-0084, Revision 4, dated August 2, 1990, and a low frequency eddy current (LFEC) inspection in accordance with Part II.B. in the Accomplishment Instructions of the service bulletin.

1. If no corrosion is detected:

a. Repeat the external visual inspection at intervals not to exceed 15 months; and

b. Repeat theLFEC inspection at intervals not to exceed 30 months; and

c. Within 48 months after the effective date of this AD, conduct an internal close visual inspection in accordance with Part II.C. in the Accomplishment Instructions of the service bulletin. Repeat this inspection at intervals not to exceed 48 months.

2. If corrosion is detected, repair prior to further flight, in accordance with Part III of the Accomplishment Instructions of the service bulletin.

B. Within the next 3,000 landings or 30 months after the effective date of this AD, whichever occurs first, accomplish a high frequency eddy current (HFEC) inspection in accordance with Part II.D. of the Accomplishment Instructions of Boeing Service Bulletin 727- 53-0084, Revision 4, dated August 2, 1990.

1. If no cracking is detected, repeat the inspection at intervals not to exceed 4,000 landings or 48 months, whichever occurs first.

2. If cracking is detected, repair before further flight, in accordance with Part III in the Accomplishment Instructions of the service bulletin.

C. If the sealant has deteriorated but no cracking or corrosion is detected as a result of the inspections required by paragraphs A. and B. of this AD, reseal in accordance with Figure 5 or 6, as applicable, of Boeing Service Bulletin 727-53-0084, Revision 4, dated August 2, 1990.

D. Modification in accordance with Part III in the Accomplishment Instructions of Boeing Service Bulletin 727-53-0084, Revision 4, dated August 2, 1990, constitutes terminating action for the inspections required by this AD for the area modified.

E. Modification in accordance with Part IV in the Accomplishment Instructions of Boeing Service Bulletin 727-53-0084, Revision 4, dated August 2, 1990, constitutes terminating action for the inspections required by paragraph B. of this AD.

F. An alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate.

NOTE: The request should be submitted directly to the Manager, Seattle ACO, and a copy sent to the cognizant FAA Principal Inspector (PI). The PI will then forward comments or concurrence to the Seattle ACO.

G. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.

All persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. These documents may be examined at the FAA, Northwest Mountain Region Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington.

This amendment (39-6835, AD 90-26-09) becomes effective on January 22, 1991.